/*
 * Copyright 2023 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package androidx.xr.glimmer.list

import androidx.compose.foundation.gestures.Orientation
import androidx.compose.runtime.Composable
import androidx.compose.runtime.remember
import androidx.compose.ui.semantics.CollectionInfo

internal fun glimmerListSemanticState(
    state: ListState,
    isVertical: Boolean,
): LazyLayoutSemanticState =
    object : LazyLayoutSemanticState {

        override val scrollOffset: Float
            get() =
                estimatedLazyScrollOffset(
                    state.firstVisibleItemIndex,
                    state.firstVisibleItemScrollOffset,
                )

        override val maxScrollOffset: Float
            get() =
                estimatedLazyMaxScrollOffset(
                    state.firstVisibleItemIndex,
                    state.firstVisibleItemScrollOffset,
                    state.canScrollForward,
                )

        override suspend fun scrollToItem(index: Int) {
            state.scrollToItem(index)
        }

        override fun collectionInfo(): CollectionInfo =
            if (isVertical) {
                CollectionInfo(rowCount = -1, columnCount = 1)
            } else {
                CollectionInfo(rowCount = 1, columnCount = -1)
            }

        override val viewport: Int
            get() =
                if (state.layoutInfo.orientation == Orientation.Vertical) {
                    state.layoutInfo.viewportSize.height
                } else {
                    state.layoutInfo.viewportSize.width
                }

        override val contentPadding: Int
            get() = state.layoutInfo.beforeContentPadding + state.layoutInfo.afterContentPadding
    }

@Composable
internal fun rememberGlimmerListSemanticState(
    state: ListState,
    orientation: Orientation,
): LazyLayoutSemanticState {
    return remember(state, orientation) {
        glimmerListSemanticState(state = state, isVertical = orientation == Orientation.Vertical)
    }
}
